With the advent of the information age, display technology has been constantly updated. OLED (organic electroluminescent display) display technology with ultra-fast response speed and slim advantages have been tremendous development.
The display of the currently OLED panel is usually the following three ways: RGB parallel pixel independent light, light color conversion and color filter and so on.
Red, green and blue (RGB) pixels emit light independently: using FMM (Fine Metal Mask) and CCD (Charge-coupled Device). First of all, preparing red, green and blue primary color luminescent centers, and then adjusting the color mixing ratio of the three-color combinations to produce a color so that the three-color OLED element emits light independently to form one pixel. The key of this technology is to improve the color purity and luminous efficiency of luminescent materials, meanwhile, the technology of metal shadow mask etching is also very important. With the OLED display colorization, high resolution and large area, the metal shadow mask etching technology directly affects the quality of the display panel screen, so the metal shadow mask graphics dimensional accuracy and positioning accuracy made more stringent requirements.
Light color conversion: combining a blue OLED with a light color conversion film array, preparing a device emitting blue OLEDs, and then exciting the light color conversion materials to obtain red light and green light by using the blue light, thus obtaining full color. The key of this technology is to improve the color purity and efficiency of light color conversion materials. This technique eliminates the need for FMM and alignment techniques, requiring only blue OLED elements to be evaporated. However, its disadvantage is that the light color conversion material easily absorbs the blue light in the environment, causing the contrast of the image to decrease, and the light guide also causes the problem of the picture quality being degraded.
Color filter: use of white OLED combined with color filter, similar to the liquid crystal display color filter film production technology. First preparing white OLED devices, and then getting the three primary colors through the color filter, combining with the three primary colors to achieve color display. The key to this technology is to get white light with high efficiency and high purity. Its production process without FMM and registration technology, but the use of this technology through the color filter caused by the loss of up to two-thirds.
Now the mainstream of the OLED panel display type is red, blue and green three primary color pixels in the same side of the panel side by side distribution, through the control of the drive circuit to achieve the screen display. Such display modes increase the pixel resolution by compressing the pixel arrangement space, and now the common red, blue and green three-color pixel independent light-emitting preparation process needs five FMM and CCD processes. This brings the complex process, low yield, high preparation costs and other issues.